Question: Multiply.
$19 \times85$ and $19 \times 0.85$ multiply the same digits in the same order. So, the product of both problems will also have the same digits in the same order. Let's multiply $19\times 85$. Then we can estimate to place the decimal point in the product of $19 \times 0.85$. $\begin{aligned} 19&\\ \underline{ \times 85}&\\ 45}\\ 50}\\ 720}\\ \underline{+800}}\\ 1{,}615 \end{aligned}$ Let's estimate to place the decimal in $19 \times 0.85$. $\begin{aligned} 19 \times 0.85 &\approx 20\times 1\\\\ &\approx 20 \end{aligned}$ Where can we place the decimal in $1{,}615$ to get a product close to $20$ ? $16.15 =19 \times 0.85$